EAMON Gilmore's attempt to outflank Provisional Sinn Fein from the left with Labour's policies on tax cuts, the EU/IMF bailout and the budget deficit suggests a distinct departure from past Labour calculations.
Previous Labour leaders who went into coalition with Fine Gael were not looking over their left shoulders in the same dramatic manner as Gilmore has been this week.
Brendan Corish and Dick Spring worked well with taoisigh Liam Cosgrave and Garret FitzGerald during their respective ministries, though there were major disagreements on policy within certain narrowly defined areas.
Gilmore's claim that Fine Gael were 'Celtic Tories' cut from the same shabby cloth as Fianna Fail might have been mere rhetorical excess in an election week, but it might also symbolise a kind of social and intellectual contempt for Fine Gael that his predecessors in Labour lacked.
It is well known, for example, that the closest working relationship in the Fine Gael-Labour cabinet between 1973 and 1977 was that formed between Liam Cosgrave and the Labour Minister for Posts & Telegraphs, Conor Cruise O'Brien.
Though Cosgrave would often take his Tanaiste Brendan Corish into his office for a whiskey when coalition relations needed soothing, Ireland's most personally conservative Taoiseach became particularly fond of O'Brien -- a socialist divorcee who held the Schweizer chair in history in godless New York University before running for the Dail in 1969.
Garret FitzGerald has written about his own personal respect for his young Tanaiste Dick Spring during their fraught government between 1982-87, though he also recognised that "it might take some time for Spring to feel entirely comfortable with someone so much older" as Taoiseach.
The crucial elixir in both these sets of relationships was the confidence of the Fine Gael taoisigh in the Labour Party's judgement on Northern Ireland.
Corish had supported the Fethard-on-Sea boycott in 1954, but by 1973 he refused to give an inch to the sectarian fundamentalism that drove the Provisional campaign.
And Spring would prove himself tough as old boots during the H-Block campaigns in the early 1980s, especially during the PIRA-backed marches in Dublin, which tested the gardai almost to breaking point on one occasion.
There is no comparable Northern Ireland problem to vex a government led by Enda Kenny and Gilmore, but that said, the Labour leader's decision to match Provisional Sinn Fein's populist economics prompts questions about Labour's commitment to serving a full term in office.
If elected Taoiseach, Kenny will be saddled with a Labour Tanaiste who is probably the most aggressively left-wing of all his predecessors.
Kenny will not be able to call on the consoling precedents provided by the Cosgrave government.
Based on Labour's tax statements issued last week, a Kenny-Gilmore coalition might well resemble the strained, even fractious relationship between another Fine Gael Taoiseach and Labour Tanaiste.
By the time John Bruton became Taoiseach suddenly at the end of 1994, it was an open secret that he had fairly poor personal relations with Dick Spring.
Fergus Finlay and Sean Duignan explained in their respective books that their working relationship had been badly damaged by the strains of the FitzGerald government in the 1980s.
At Finance and in Industry & Commerce, Bruton was an aggressive budget-balancer who argued that the massive recession required structural reform in the economy that would fundamentally reorganise the tax system.
Spring was an equally aggressive old-style Labour spending minister facing him across the cabinet, arguing that deficits were the price any civilised society had to pay in order to create jobs and protect families from the indignity of the means-test and the poor house.
The amicable sundering of ties in that government in 1987 was something of a relief to both men. By 1994 though, both Bruton and Spring had to make it work better, now that both were running the government together.
As John Major recounted in his memoirs, the FG-Labour government did not always function properly on Northern Ireland policy, this being a fairly major departure from the way Labour ministers had worked under Fine Gael Taoisigh in the Seventies and Eighties. Major recalled several meetings in the run-up to the publication of the Framework Documents in 1995 where his officials would agree something with Bruton's officials, only to find that the prime ministerial work would be turned inside out at the next meeting between Dick Spring and Patrick Mayhew.
Major found this somewhat shambolic approach to high-wire diplomacy rather charming, but it did little for Ireland's reputation amongst the Whitehall mandarins.
Spring seemed to think that he understood the complexities of Northern Ireland better than Bruton who never had ministerial responsibility for this issue before acceding to the premiership in 1994.
He was not inclined to defer to a Taoiseach who looked back to the Home Rule era for personal inspiration.
There was something of this same barely concealed derision in Eamon Gilmore's demeanour last week, a similar lack of sympathy or even feeling for the FG traditions, something that could not be said for example about Ruairi Quinn, who was an impressively no-nonsense Minister for Finance under Bruton.
Gilmore obviously sees Kenny as inarticulate and somewhat peripheral to Fine Gael policy. He risks making the same mistake made about the equally monosyllabic Liam Cosgrave before 1973.
Public reticence is not always to be conflated with intellectual timorousness, as Garret FitzGerald found out very quickly once he joined Cosgrave's cabinet.
Gilmore could be in for a rude surprise with Kenny.
John-Paul McCarthy holds a doctorate in Irish history from Oxford